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Tradescantia-micronucleus assay on the water quality of lake Hongzhe in Jiangsu Province, China
Mutation Research 426 Ž1999. 155–157 www.elsevier.comrlocatermolmut Community address: www.elsevier.comrlocatermutres
Tradescantia-micronucleus assay on the water quality of lake Hongzhe in Jiangsu Province, China Guangli Yang Huaiyin EnÕironmental Monitoring Station, Huaiyin, Jiangsu ProÕince, China Received 8 February 1998; accepted 8 March 1998
Abstract Lake Hongzhe, located in the northwest part of the Province of Jiangsu, is one of the five largest freshwater lakes in China. It has great economic importance for the fishery industry and for scenic beauty. Effluents from the industrial development and runoff from farm chemicals have contributed increasingly to the water pollutants in recent years. For many years, water quality has been monitored only by chemical analysis. No information is provided from the chemical analysis on the toxicity level of the aquatic forms in the lake and the ecosystems that directly or indirectly depend upon this water. In the present study, some chemical components were determined from water samples collected from the lake and in addition, the genotoxicity of the same water samples was determined using the Tradescantia-micronucleus bioassay. Results confirmed that the quantity of pollutants in the water bears some relationship with the genotoxicity in terms of chromosome damage. High nitrates and nitrogen content were the main contributing factors observed. The use of bioassays such as the Tradescantia-micronucleus test together with chemical analyses to monitor the water quality is highly recommended for the general practice for the environmental monitoring stations through the country. q 1999 Elsevier Science B.V. All rights reserved. Keywords: Micronucleus assay; Water pollution; Chemical analysis; Genotoxicity; Tradescantia
1. Introduction Lake Hongzhe is located in the northwestern part of Jiangsu Province, China. It is one of the largest bodies of freshwater in the Huai River area, and is one of the five major lakes in China. This lake is geographically located between 33806X and 33840X latitude and 118810X and 118855X longitude in a climate which is characterized as the warmer portion of the temperate zone. The total surface area is about 1960 km2 . It has great economic value owing to its
rich fishing industry and its beautiful scenery. Industrial development and farming have been contributing pollutants into the lake and the quality of the water has been steadily declining and damaging the ecosystems in and around the lake. Protection of this lake is an urgent task. For many years, monitoring the water quality of the lake has been limited to chemical means. This is the first time, a bioassay using the Tradescantia-micronucleus ŽTrad-MCN. assay has been applied to determine the genotoxicity of water samples of this lake w1x. The results of this
0027-5107r99r$ - see front matter q 1999 Elsevier Science B.V. All rights reserved. PII: S 0 0 2 7 - 5 1 0 7 Ž 9 9 . 0 0 0 6 0 - 3
G. Yang r Mutation Research 426 (1999) 155–157
156
study will provide pertinent information on the genotoxicity level of the water that can be extrapolated to living beings, including humans.
2. Materials and methods Water samples were collected from four different sites around the lake, i.e., Gaojian City, Jiangba City, Laoshan Village and east of Chenghe Village ŽFig. 1.. The pH values of the water samples were adjusted by weak HCl or NaOH to near 7 before testing. Tradescantia clone 03 was used for the Tradescantia-micronucleus ŽTrad-MCN. tests. Plant cuttings that bear young inflorescences Ž15 cuttings per experimental group. were treated by the water samples in a 500 ml beaker for 6 h. The treated and control plant cuttings were placed under artificial light for a 24 h recovery period. There was a total of eight treated groups Žtwo groups for each of the four water samples. plus one negative control Žclean tap water., and three positive control concentrations ŽHgCl solutions at 30, 150 and 300 mgrl.. The standard protocol of Trad-MCN assay was used for treatment, fixation, slide preparation, and scoring micronuclei frequencies w2x. Means and standard deviations of each of the experimental groups were obtained from the MCN frequencies scored Ž1500 tetrads scored per group.. The Dunnett’s t-test w3x was used to determine the significant differences between the control and the four treated groups.
3. Results and discussion Water samples were chemically analyzed for nitrogen, phosphorous, iron, nitrates and oxygen con-
Table 1 Water samples chemically analyzed for nitrogen, phosphorous, iron, nitrates and oxygen content from lake Hongzhe Žin mgrl. Sampling sites
Total Total Total Nitrates Oxygen nitrogen phosphorus iron
Gaojian Jiangba Laoshan East Chenghe
7.56 6.26 7.37 3.32
0.07 0.06 0.08 0.15
0.85 0.56 0.47 0.53
3.74 5.48 4.72 1.35
1.4 0.5 2.1 1.9
Table 2 MCN frequencies scored from water samples from each of the four sites and negative and positive control groups Sampling sites and controls
MCNr100 tetrads " S.D.
Significance Ž0.05.
Gaojian Jiangba Laoshan East Chenghe Tap water a HgCl 300 mgrlb
10.90"1.25 9.74"0.39 9.40"0.71 8.25"0.22 6.84"0.30 12.60"1.76
q q q –
a b
q
Negative control. Positive control.
tent. The quantities of each of the five parameters measured Žexpressed in mgrl. are given in Table 1. The MCN frequencies scored from each of the four treated and one negative control and one positive group are given in Table 2. Based upon the MCN frequencies and the results of the chemical analyses of the four water samples, the high nitrate and total nitrogen contents seem to be the contributing factors for the elevated genotoxicity. The highly polluted water at the Goajian site reached almost the same toxicity level as the 300 mgrl mercuric chloride sample which was used as a positive control. The results indicate that the TradMCN assay clearly demonstrated the damaging effect of the polluted water of lake Hongzhe on the chromosomes of the germ cells of the Tradescantia plants. The Trad-MCN test and other reliable bioassays can provide a first alert of the hazardous state of water quality under real life conditions w4x. It is suggested that the Trad-MCN test should be routinely used to monitor the water quality of the lake and not solely rely on chemical monitoring. Thus, with the addition of bioassays such as the Trad-MCN, Tradescantia stamen hair mutation ŽTrad-SHM., and AlliumrVicia root chromosome aberration ŽAVRCA. assays, the monitoring stations throughout the country using these assays can better serve the true missions of environmental protection w5x. This chemical and biological monitoring strategy has long been the goal of the International Program on Chemical Safety, WHO, and currently promoted by the International Program on Plant Bioassays under the auspices of the United Nations Environment Program w6x.
G. Yang r Mutation Research 426 (1999) 155–157
References w1x National Environmental Monitoring Center, Guidelines for Environmental Monitoring Techniques, Bio-monitoring Division, Government Publication, Bejing, PRC, 1986. w2x T.H. Ma, G.L. Cabrera, R. Chen, B.S. Gill, S.S. Sandhu, A.L. Vandenberg, M.F. Salamone, Tradescantia-micronucleus bioassay—a collaborative study on Plant Genotoxicity Bioassays for the International Programme on Chemical Safety, WHO, The United Nations, Mutat. Res. 310 Ž1994. 221–230. w3x B.J. Winer, Statistical Principles in Experimental Design. McGraw-Hill, New York, 1971, pp. 202–204, 873–874.
157
w4x T.H. Ma, Application of quick and simple plant bioassays to assess the genotoxicity of environmental pollutants—detection of potential health hazards of air, water and soil contaminants, in: G.H. Degen, J.P. Seiler, P. Bentley ŽEds.., Toxicology in Transition, Proceedings of the 1994 EUROTOX Congress, Springer1, New York, 1994, pp. 420–433. w5x W.F. Grant, The present status of higher plant bioassays for the detection of environmental mutagens, Mutat. Res. 310 Ž1994. 175–185. w6x T.H. Ma, W.F. Grant, F.J. de Serres, The genotoxicity monitoring of the air, water and soil—a preliminary report of the International Program on Plant Bioassays ŽIPPB., Mutat. Res. 379 Ž1997. S99.
Tradescantia-micronucleus assay on the water quality of lake Hongzhe in Jiangsu Province, China Guangli Yang Huaiyin EnÕironmental Monitoring Station, Huaiyin, Jiangsu ProÕince, China Received 8 February 1998; accepted 8 March 1998
Abstract Lake Hongzhe, located in the northwest part of the Province of Jiangsu, is one of the five largest freshwater lakes in China. It has great economic importance for the fishery industry and for scenic beauty. Effluents from the industrial development and runoff from farm chemicals have contributed increasingly to the water pollutants in recent years. For many years, water quality has been monitored only by chemical analysis. No information is provided from the chemical analysis on the toxicity level of the aquatic forms in the lake and the ecosystems that directly or indirectly depend upon this water. In the present study, some chemical components were determined from water samples collected from the lake and in addition, the genotoxicity of the same water samples was determined using the Tradescantia-micronucleus bioassay. Results confirmed that the quantity of pollutants in the water bears some relationship with the genotoxicity in terms of chromosome damage. High nitrates and nitrogen content were the main contributing factors observed. The use of bioassays such as the Tradescantia-micronucleus test together with chemical analyses to monitor the water quality is highly recommended for the general practice for the environmental monitoring stations through the country. q 1999 Elsevier Science B.V. All rights reserved. Keywords: Micronucleus assay; Water pollution; Chemical analysis; Genotoxicity; Tradescantia
1. Introduction Lake Hongzhe is located in the northwestern part of Jiangsu Province, China. It is one of the largest bodies of freshwater in the Huai River area, and is one of the five major lakes in China. This lake is geographically located between 33806X and 33840X latitude and 118810X and 118855X longitude in a climate which is characterized as the warmer portion of the temperate zone. The total surface area is about 1960 km2 . It has great economic value owing to its
rich fishing industry and its beautiful scenery. Industrial development and farming have been contributing pollutants into the lake and the quality of the water has been steadily declining and damaging the ecosystems in and around the lake. Protection of this lake is an urgent task. For many years, monitoring the water quality of the lake has been limited to chemical means. This is the first time, a bioassay using the Tradescantia-micronucleus ŽTrad-MCN. assay has been applied to determine the genotoxicity of water samples of this lake w1x. The results of this
0027-5107r99r$ - see front matter q 1999 Elsevier Science B.V. All rights reserved. PII: S 0 0 2 7 - 5 1 0 7 Ž 9 9 . 0 0 0 6 0 - 3
G. Yang r Mutation Research 426 (1999) 155–157
156
study will provide pertinent information on the genotoxicity level of the water that can be extrapolated to living beings, including humans.
2. Materials and methods Water samples were collected from four different sites around the lake, i.e., Gaojian City, Jiangba City, Laoshan Village and east of Chenghe Village ŽFig. 1.. The pH values of the water samples were adjusted by weak HCl or NaOH to near 7 before testing. Tradescantia clone 03 was used for the Tradescantia-micronucleus ŽTrad-MCN. tests. Plant cuttings that bear young inflorescences Ž15 cuttings per experimental group. were treated by the water samples in a 500 ml beaker for 6 h. The treated and control plant cuttings were placed under artificial light for a 24 h recovery period. There was a total of eight treated groups Žtwo groups for each of the four water samples. plus one negative control Žclean tap water., and three positive control concentrations ŽHgCl solutions at 30, 150 and 300 mgrl.. The standard protocol of Trad-MCN assay was used for treatment, fixation, slide preparation, and scoring micronuclei frequencies w2x. Means and standard deviations of each of the experimental groups were obtained from the MCN frequencies scored Ž1500 tetrads scored per group.. The Dunnett’s t-test w3x was used to determine the significant differences between the control and the four treated groups.
3. Results and discussion Water samples were chemically analyzed for nitrogen, phosphorous, iron, nitrates and oxygen con-
Table 1 Water samples chemically analyzed for nitrogen, phosphorous, iron, nitrates and oxygen content from lake Hongzhe Žin mgrl. Sampling sites
Total Total Total Nitrates Oxygen nitrogen phosphorus iron
Gaojian Jiangba Laoshan East Chenghe
7.56 6.26 7.37 3.32
0.07 0.06 0.08 0.15
0.85 0.56 0.47 0.53
3.74 5.48 4.72 1.35
1.4 0.5 2.1 1.9
Table 2 MCN frequencies scored from water samples from each of the four sites and negative and positive control groups Sampling sites and controls
MCNr100 tetrads " S.D.
Significance Ž0.05.
Gaojian Jiangba Laoshan East Chenghe Tap water a HgCl 300 mgrlb
10.90"1.25 9.74"0.39 9.40"0.71 8.25"0.22 6.84"0.30 12.60"1.76
q q q –
a b
q
Negative control. Positive control.
tent. The quantities of each of the five parameters measured Žexpressed in mgrl. are given in Table 1. The MCN frequencies scored from each of the four treated and one negative control and one positive group are given in Table 2. Based upon the MCN frequencies and the results of the chemical analyses of the four water samples, the high nitrate and total nitrogen contents seem to be the contributing factors for the elevated genotoxicity. The highly polluted water at the Goajian site reached almost the same toxicity level as the 300 mgrl mercuric chloride sample which was used as a positive control. The results indicate that the TradMCN assay clearly demonstrated the damaging effect of the polluted water of lake Hongzhe on the chromosomes of the germ cells of the Tradescantia plants. The Trad-MCN test and other reliable bioassays can provide a first alert of the hazardous state of water quality under real life conditions w4x. It is suggested that the Trad-MCN test should be routinely used to monitor the water quality of the lake and not solely rely on chemical monitoring. Thus, with the addition of bioassays such as the Trad-MCN, Tradescantia stamen hair mutation ŽTrad-SHM., and AlliumrVicia root chromosome aberration ŽAVRCA. assays, the monitoring stations throughout the country using these assays can better serve the true missions of environmental protection w5x. This chemical and biological monitoring strategy has long been the goal of the International Program on Chemical Safety, WHO, and currently promoted by the International Program on Plant Bioassays under the auspices of the United Nations Environment Program w6x.
G. Yang r Mutation Research 426 (1999) 155–157
References w1x National Environmental Monitoring Center, Guidelines for Environmental Monitoring Techniques, Bio-monitoring Division, Government Publication, Bejing, PRC, 1986. w2x T.H. Ma, G.L. Cabrera, R. Chen, B.S. Gill, S.S. Sandhu, A.L. Vandenberg, M.F. Salamone, Tradescantia-micronucleus bioassay—a collaborative study on Plant Genotoxicity Bioassays for the International Programme on Chemical Safety, WHO, The United Nations, Mutat. Res. 310 Ž1994. 221–230. w3x B.J. Winer, Statistical Principles in Experimental Design. McGraw-Hill, New York, 1971, pp. 202–204, 873–874.
157
w4x T.H. Ma, Application of quick and simple plant bioassays to assess the genotoxicity of environmental pollutants—detection of potential health hazards of air, water and soil contaminants, in: G.H. Degen, J.P. Seiler, P. Bentley ŽEds.., Toxicology in Transition, Proceedings of the 1994 EUROTOX Congress, Springer1, New York, 1994, pp. 420–433. w5x W.F. Grant, The present status of higher plant bioassays for the detection of environmental mutagens, Mutat. Res. 310 Ž1994. 175–185. w6x T.H. Ma, W.F. Grant, F.J. de Serres, The genotoxicity monitoring of the air, water and soil—a preliminary report of the International Program on Plant Bioassays ŽIPPB., Mutat. Res. 379 Ž1997. S99.